Computers are used to process information. "Information", as used herein, includes computer programs, the data which a program may process, the addresses at which the data is to be stored, and, generally, anything which may be held in a computer memory. Information is copied into the computer's memory from some storage medium. The computer's processing unit processes the information in the memory until it is in the desired form, and then copies the processed information out to a storage medium, which is generally (although not invariably) the same as the medium from which the unprocessed information was copied. The processed information (and, often, some or all of the unprocessed information) remains in the computer's memory.
This remaining information is generally located in consecutive addresses. Such consecutive addressing may be undesirable for any of a number of reasons. Certain memory addresses may be overused, while others are hardly used at all. If the information is sensitive, consecutive addressing may ease the task of an unauthorized person who seeks access to it, even if it is erased or overwritten before the memory is returned to non-sensitive use. Such erasing or overwriting procedures may be both tedious and not completely effective. Other reasons will occur to those skilled in the art.
Likewise, the data word stored at each address may reside in only a few of the many bits available at that address. This may also be undesirable, for reasons similar to those for consecutive addressing: resource misallocation, reduced security, and the like.